Two Canadian CF-18 fighter jets, part of the North American Aerospace Defense Command, scrambled from Cold Lake, Alberta, and turned away the Russian Tupolev Tu-95 Bear bomber less than 24 hours before Obama's Feb. 19 visit with Canadian Prime Minister Stephen Harper, MacKay said.

The Norad fighter jets "met a Russian aircraft that was approaching Canadian airspace," he said at a news conference. "They sent very clear signals that the Russian aircraft was to turn around -- turn tail -- to its own airspace, which it did."

MacKay said he didn't know if the near-incursion was a deliberate provocation or an accident.

"I am not going to stand here and accuse the Russians of having deliberately done this during the presidential visit but it was a strong coincidence, which we met with a presence, as we always do, with F-18 fighter planes," he said.

Russian attempts to violate Canadian airspace, which The Globe and Mail said stopped after the 1991 fall of the Soviet Union, resumed "just a few years ago," MacKay said, after Russian President Vladimir Putin declared Russia would take a more active role in asserting itself.

"That apparently includes coming close to and up to Canadian airspace," MacKay said.

Such violations are "not a game at all," MacKay said with Canadian defense staff chief Gen. Walter Natynczyk and Norad commander U.S. Air Force Gen. Gene Renuart at his side.